Gas turbine engine disks commonly have slots for attaching blades which are generally axially oriented. These slots have a profile which mates with the roots of the blades, and have a configuration which will retain the blades in the slots under the applied centrifugal forces incurred in operation of the engine. The slot profiles are often of a “fir-tree” configuration to increase the load bearing area in the slot, although other configurations are also employed.
The turbine disk slots for mounting turbine blades typically have a a sharp edge entrance for airflow. The sharp edge entrance causes an unfavorable airflow separation at the slot inlet, and undesirably generates an increased heat transfer rate because of airflow reattachment.